"This" is the read-option, run out of the pistol or some other formation. It wasn't a tool that Young had available to him, not when he came into the league with Tampa Bay and not when he made his playoff debut as the 49ers' starter against the Redskins in January of 1993.

Back in Young's day, you were either a running quarterback or a throwing quarterback. He was one of the very few who eventually made the transition to the point of being extremely dangerous on both fronts.

Kaepernick resists being labeled. When asked in the immediate wake of his amazing night against Green Bay whether he considers himself a runner or a thrower, he said, "I don't want to be categorized."

Being pigeonholed hurt him when he was in high school and again when he was coming out of Nevada for the NFL draft.

"I feel like pretty much my whole life I've been categorized as a runner," Kaepernick said this week.

But Young is seeing a difference in the new generation of mobile quarterbacks: the ability to be two things at once.

"They're better trained," he said. "Everyone knows they're athletic, but now they're being trained as quarterbacks, as both a runner and a thrower. They're starting younger and they're not thinking, 'Hey, these are two really hard things that I'm doing.'"

Young had to learn to stay in the pocket and not rely on his mobility. He has often said that it wasn't until he made that transition that he truly reached his potential. But he sees the read-option system as a huge benefit for young players, who can use their athleticism while they're learning what it takes to be an NFL quarterback.

"What a tremendous bridge to get started and put down a foundation," Young said. "On the field you can be confident, because you always have that weapon in your back pocket."

Young thinks that what we witnessed Saturday night is part of a bigger transition in NFL offenses. Of course, he thought he was seeing it before, when he was exiting the game and Michael Vick was coming in.

"I thought Vick might be the prototype," Young said. "And then Brady and Manning broke every record and didn't move an inch."

But Young thinks this change might be more lasting. He's sure that defenses will eventually catch up, but described them as, for the moment, "baffled."

"There are guys today doing things that have never been contemplated, that Randall Cunningham never thought about," Young said. "The athleticism of defenses will catch up, but at what cost? You can't stop one thing."

Kaepernick is too young to have viewed Young, who rushed for 4,239 yards in his Hall of Fame career, as a role model. But he watched Vick, Vince Young and Donovan McNabb, plus old tape of Cunningham - all quarterbacks who challenged defenses with their mobility.

Young's athleticism and scrambling ability was often a game changer. But in his early years, defenses knew that if they kept him in the pocket, they could force him into a mistake.

With that memory in hand, Young warned before Kaepernick's first start against Chicago that the inexperienced quarterback needed to be cautious. Working that Monday night game as a broadcaster, Young advised Kaepernick to rely on his defense and not do anything to lose the game. As we know, Kaepernick did anything but play it safe, opening it up against the Bears.

Last week, Young again wondered how Kaepernick would respond in his playoff debut.

"He did what I kind of expected, made the big blunder," Young said. "And then steeled up. ... I can't be more impressed. He's something really special."

Young, once the inexperienced backup who replaced a starter, has also been impressed with how all parties have handled what could be an awkward, even damaging transition from Alex Smith to Kaepernick.

"I'm proud of how Alex handled it, how the team handled it, how Colin handled it," he said. "It could have been a real problem. It was a big deal. That should not be underestimated. And it went as well as it could go."

Young's transition to starter came in the early 1990s, and was fraught with more emotion and anxiety because of all Joe Montana had accomplished and what he meant to the 49ers. Young's first postseason start was against defending champion Washington in the NFC divisional playoff game. He completed 20 of 30 passes for 227 yards, two touchdowns and an interception. He also ran for 73 yards on eight carries in the 49ers' 20-13 win (they lost to Dallas in the NFC Championship game the next week).

He wasn't quite the cool customer that Kaepernick seemed to be on Saturday.

"I was nervous, of course I was," Young remembered. "But that's how I did it. Everyone does it differently."

"And if you recall, Joe was on the sideline."

And there wasn't a read-option in place to give Young confidence. No wonder he's just the tiniest bit envious.

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